Seismic performance evaluation of beam-column joints for prestressed RC buildings with high performance materials

Four one-third-scale prestressed RC (PRC) interior beam-column joints were tested by the authors. The main parameters of this test were the prestressing force and the bond condition between the grout and prestressing tendons passing through a joint. Prestressing force was applied at the ends of the beams using the post-tensioning method. These beam-column joints were analyzed using a nonlinear finite element method (FEM). The analysis was carried out by considering the bond between the grout and prestressing tendons as in the tests. All specimens failed in joint shear failure both in the tests and in the FEM analysis. The FEM results show a good agreement with the test results on the maximum story shear forces and the failure mode. From the experimental and FEM results, the effects of the prestressing force and the bond condition between the grout and prestressing tendons on the joint shear capacity were examined. The following conclusions can be made from the detailed investigations: (1) The joint shear cracking strength obtained from the tests was almost constant regardless of the level of the prestressing force. However, the angles of shear cracking in the joint changed with the prestressing forces. (2) The shear capacity of the joint was not much affected by the prestressing forces. (3) Because the bond between the grout and rounded tendons deteriorated at an early loading stage, the effect of the bond conditions on the joint shear capacity was not significant.